It is known to deposit thin films that contain known analytes onto a substrate from an analyte containing liquid. For instance, Patents to Pfeiffer et al., U.S. Pat. Nos. 8,531,665, 8,493,565, 8,130,375 and 7,817,266 describe Small Cells into which analyte containing fluid is caused to flow, to the end that analyte present in said fluid deposits onto a substrate. Provision for an ellipsometer beam to be directed onto said thin analyte containing film is also present, and during use a polarized beam of electromagnetic radiation is caused to interact with the thin film on said substrate and then enter a detector.
It is also known to characterize effective surfaces of substrates comprising pores, by transiently causing solvents to permeate thereinto long enough to allow ellipsometric investigation thereof, for a sequence of solvent values. Known relevant references are: Patents to Baklanov et al. U.S. Pat. Nos. 6,435,008; 6,319,736, and 6,662,631; and papers by Boissire et al, titled “Porosity and Mechanical Properties of Mesoporous Thin Films Assessed by Environmental Ellipsometric Porosity”, Langmuir 2005, 21, 12362-12371; by Xinxin and Vogt Titled “Carbon Dioxide Mediated Synthesis of Mesoporous Silica Films: Tuning Properties using Pressure”, Chem. Mater. Amer. Chem. Soc., Web Apr. 18, 2008. and by Vogt et al., titled “Characterization of Ordered Mesoporous Silica Films Using Small-Angle Neutron scattering and X-ray Porosimetry”, Chem. Mater., 17, 1398-1408. Note that said references do not describe use at atmospheric pressure.
In further disclosure, Applicants know of no prior art systems which rely on direct measurement of partial pressure in an open (to the ambient) cell. Known prior art systems use closed cells and apply a feedback system to control a solvent flow rate into said open cell to set a desired partial pressure. In addition, known partial pressure monitors are suitable only when water is the solvent involved. As disclosed in the following in this Specification, the present invention applies open chambers in which partial pressures are developed. Further, as disclosed in the following, the present invention is not limited to using only water as a solvent.
What is, to the inventor's knowledge, not previously known is a system and method for investigating changes in optical properties of a porous effective substrate surface related to, for instance, effective surface depth and refractive index, pore size, pore volume and pore size distribution at atmospheric pressure, said system enabling the flowing of a gas that contains at least one solvent therein which is flowed over said substrate surface at a monitored temperature, over a sequence of different known solvent partial pressures. Such a system and method are disclosed herein.